WAEC SSCE - Geography - 1988

Detalhes da Resposta

Detalhes da Resposta

The factor that least explains the pattern of population distribution in Nigeria is the occurrence of earthquakes in certain areas. This is because earthquakes are not a common occurrence in Nigeria, and even when they occur, they are usually mild and do not cause significant damage to human settlements. Therefore, earthquakes cannot have a significant impact on the distribution of population in Nigeria. On the other hand, the other factors listed have played a significant role in shaping the population distribution in Nigeria. Arab slave raiding, for instance, led to the movement of people away from certain areas. The stability of government of the old kingdoms attracted people to settle in those areas, while physical factors such as rainfall influenced where people could engage in agriculture and other economic activities. The movement of people from one place to another has also contributed to population distribution patterns in Nigeria.

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Asia has the largest population among the given options. As of 2021, Asia has a population of over 4.6 billion people, which is more than half of the world's total population. In comparison, Africa has a population of around 1.3 billion people, Europe has a population of around 747 million people, North America has a population of around 594 million people, and South America has a population of around 430 million people. Therefore, the correct answer is Asia.

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Detalhes da Resposta

When the roof of a coastal cave collapses, it forms a geo. A geo is a narrow, steep-sided inlet, created when the roof of a cave erodes and collapses, and the sea fills the resulting hole. The collapsed roof is typically made of softer rocks, while the sides of the geo are composed of harder, more resistant rocks. The term "geo" is most commonly used in Scotland, but similar coastal features can be found in other parts of the world under different names, such as "sea cave" or "natural arch".

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The statement that is not true of the Solar System is: "All the plantes rotete around the sun." The correct statement is "All the planets rotate around their own axis." This means that each planet spins or rotates around an imaginary line that runs through its center. The rotation of the planets causes day and night on the planet. On the other hand, the planets also revolve around the sun in their orbits. The sun is at the center of the solar system, and it provides energy to the system through its rays, which the planets absorb. Thus, all the options are true except the one mentioned above.

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The volcanic plateau among the given options is "Deccan". A volcanic plateau is a large, flat, and elevated landform that is formed from the accumulation of volcanic material over time. Deccan plateau is located in India and is one of the largest volcanic plateaus in the world, covering an area of over 500,000 square kilometers. The Deccan plateau was formed by a series of volcanic eruptions that occurred millions of years ago. The lava flows from these eruptions spread out over a large area, and over time, they cooled and solidified, forming a thick layer of basaltic rock. The plateau is also characterized by many volcanic features, such as cones, vents, and fissures. The other options listed are not volcanic plateaus. Kukuruku is not a known geological feature, Terra Rosa is a type of soil, Graben is a type of geological structure, and Atlas is a mountain range.

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During wave actions, the rush of water onshore is called "swash". Swash is the movement of water up the beach after a wave breaks. It is responsible for carrying sand and other debris up the beach, and is an important process in shaping the beach and creating the intertidal zone. The opposite movement of water back down the beach is called "backwash".

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When you observe the wind vane, the head of the arrow shows the direction from which the wind is blowing. The wind vane is an instrument used to measure the direction of the wind. It consists of an arrow-like object mounted on a vertical rod, which freely rotates about the rod. The arrow has a larger surface area on one end than the other, causing it to point in the direction from which the wind is coming. The head of the arrow points to the direction from which the wind is blowing while the tail of the arrow is aligned with the opposite direction, giving an indication of the wind's direction.

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The question is asking to identify the country that is NOT an important timber producing country in Africa. To answer this, we need to look for the country that is not known for producing timber in Africa. The four options, Nigeria, Ghana, Cote d'Ivoire, and Zaire, are all countries that have significant timber production industries. However, Mauritania is not known for timber production and is primarily a desert country with little forest cover, so the correct answer is Mauritania.

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Interdependence within the ecosystem means that the different components of the ecosystem interact with one another. They depend on one another for survival, and changes in one component can have an effect on other components. For example, plants and animals depend on each other for food, shelter and pollination. Plants absorb carbon dioxide and release oxygen, while animals breathe in oxygen and release carbon dioxide. Decomposers such as bacteria and fungi break down dead organic matter, and release nutrients back into the soil, which are taken up by plants. This interaction between components creates a balance in the ecosystem, which helps to regulate the population of different organisms and maintain the health of the ecosystem as a whole.

Detalhes da Resposta

Detalhes da Resposta

Detalhes da Resposta

The question is asking which option is not an objective of ECOWAS. ECOWAS stands for Economic Community of West African States and it is a regional intergovernmental organization that aims to promote economic integration among its member states. It was founded in 1975 and currently has 15 member states. The objectives of ECOWAS include promoting economic cooperation, eliminating trade restrictions, promoting a unified currency system, promoting cultural, social, and political ties, and promoting a unified budgetary system. Therefore, to answer the question, we need to identify the option that is not one of the objectives of ECOWAS. The option that is not among the objectives of ECOWAS is "Promotion of a unified budgetary system". Therefore, the answer to the question is "Promotion of a unified budgetary system".

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Detalhes da Resposta

The rapid exhaustion of non-renewable natural resources may least be aided by inadequate technology. This is because inadequate technology means that natural resources are being used inefficiently and wastefully, which can lead to their rapid depletion. On the other hand, increased urbanization, reckless exploitation, excessive demand, and natural disasters can all contribute to the rapid exhaustion of non-renewable resources. Increased urbanization can lead to increased demand for resources and the destruction of natural habitats. Reckless exploitation involves using resources without regard for their long-term availability or impact on the environment. Excessive demand means that resources are being used at a rate that exceeds their natural replenishment rate. Natural disasters can cause widespread damage and destruction to natural resources, which can take years to recover from. Therefore, to address the rapid exhaustion of non-renewable resources, it is essential to develop and implement appropriate technologies that promote their efficient and sustainable use.

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The by-products of crude oil can be used to make a wide range of products such as plastics, synthetic rubber, detergents, and insecticides, among others. However, glass is not made from crude oil by-products. Glass is made from natural materials such as silica, which is found in sand, quartz, and other minerals. The process of making glass involves melting these materials at high temperatures, then cooling and shaping them into the desired form. Although crude oil is an important source of energy and raw materials for many industries, it is not used in the production of glass.

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Detalhes da Resposta

Depositional plains refer to areas of land where sediment and debris have been deposited over time by natural processes such as erosion, wind, or water. Among the options listed, the one that does not fit this definition is structural plains. Structural plains are formed as a result of tectonic activity and are characterized by relatively flat terrain with little to no topographical relief.

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The concept of environmental balance means that an ecosystem functions best when all its components are in a state of harmony and balance. This means that each component, such as plants, animals, and microorganisms, plays a role in maintaining the health of the ecosystem. When one component is altered, it can have a ripple effect on other components, potentially leading to negative consequences. For example, if there is a decline in the population of a certain plant species, it may affect the food supply of animals that depend on it, which in turn may affect predators that depend on those animals. This could result in a cascade of changes that ultimately disrupt the balance of the ecosystem. Therefore, altering one component of an ecosystem can result in the acceleration, minimization, or even reversal of processes within the system, and it is important to maintain a state of balance in order to stabilize the processes within the system.

Detalhes da Resposta

Detalhes da Resposta

The local winds mentioned in the question are Sirocco, Leveene, Mistral, and Bora. Among these winds, Sirocco is a hot wind that originates from the Sahara desert and blows across the Mediterranean Sea towards Europe. Leveene, Mistral, and Bora are not hot winds, as they originate from cold regions and bring cold air with them. Leveene blows from the land towards the sea in coastal areas, Mistral blows from the Alps towards the Mediterranean Sea, and Bora blows from the east coast of the Adriatic Sea towards the west. Therefore, the correct answer is (a) l and ll only.

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The correct option is: "Cities and rural areas depend on each other." Urban areas and rural areas have a symbiotic relationship where they depend on each other. Urban areas depend on the rural areas for agricultural products, raw materials, and other resources, while the rural areas depend on the urban areas for manufacturing, trade, and other economic activities. The relationship between urban and rural areas is essential for the economic, social, and cultural development of a country.

Detalhes da Resposta

Detalhes da Resposta

Detalhes da Resposta

Crude oil from Nigeria is transported to Europe through the "South-Atlantic" sea route. This route runs from the Niger Delta region of Nigeria, through the Gulf of Guinea, and across the South Atlantic Ocean to the refineries in Europe. The South-Atlantic sea route is one of the major shipping routes for crude oil transportation, as Nigeria is one of the largest oil-producing countries in Africa. The oil is transported in large tankers, which are specially designed to carry liquid cargo, and they can travel long distances across the open ocean. The other sea routes listed do not connect Nigeria to Europe. The North-Atlantic route runs between North America and Europe, the Trans-Pacific route connects Asia and North America, the Far-East route connects Asia with the western Pacific and Indian Ocean, and the Trans-Indian route connects the Indian Ocean and the western Pacific.

Detalhes da Resposta

Detalhes da Resposta

The correct option is: "receives a smaller amount of fresh water than the latter." The salinity of a body of water is determined by the amount of salt (or other dissolved solids) that is present in the water. In general, the more salt that is present in the water, the higher the salinity will be. The Red Sea and the Mediterranean Sea are both bodies of saltwater. However, the Red Sea is known to have a higher degree of salinity than the Mediterranean Sea. This is because the Red Sea receives a smaller amount of fresh water than the Mediterranean Sea. The Mediterranean Sea is connected to the Atlantic Ocean by the Strait of Gibraltar. This connection allows for a continuous flow of water into the Mediterranean Sea. The Red Sea, on the other hand, is located in a hot and arid region of the world, and it receives a much smaller amount of fresh water from rivers and streams. The lack of fresh water input into the Red Sea means that there is less dilution of the salt that is already present in the water. This results in a higher degree of salinity in the Red Sea as compared to the Mediterranean Sea.

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The correct statement about the Sokoto plains is that it is not an area of inland drainage. The Sokoto plains are a large expanse of low-lying flat land in northwestern Nigeria that is drained by the Sokoto River and its tributaries, including the Rima River. This means that the area is not an inland drainage area, as the water from the rivers flows outwards towards the Atlantic Ocean. The other statements are incorrect. The Sokoto plains do not lie in the middle of the country nor do they border the Rivers Benue and Niger. They are not a pear-shaped upland area, as they are actually low-lying plains. They also do not consist of the basement complex rocks, which are found in other parts of Nigeria. Finally, the Sokoto plains are not dissected by rift valleys and plateaus, as they are relatively flat and do not have major topographical features.

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Detalhes da Resposta

Detalhes da Resposta

A soil profile refers to the vertical section of the soil. It shows the different layers or horizons of the soil and their characteristics, such as texture, color, structure, and organic content. The soil profile helps in understanding the soil's properties, formation, and suitability for various uses such as agriculture, construction, and engineering. It is usually represented in a diagram that shows the different horizons and their depths.

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Detalhes da Resposta

The problem facing the cultivation of fruits in the Mediterranean region of Africa that is NOT listed among the options is inadequate processing methods. Fruit cultivation in the Mediterranean region of Africa faces various challenges, including long gestation periods, frost action, inadequate water, and the need for re-stocking. However, inadequate processing methods are not typically one of these challenges. Processing methods for fruits can vary depending on the type of fruit and its intended use, but these methods are usually well-established and widely used in the region. The main challenges facing fruit cultivation in the Mediterranean region of Africa typically involve natural factors such as climate, soil, and water availability.

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Detalhes da Resposta

The cool temperate woodland is characterized by sparse undergrowth and broad-leaved deciduous trees. This means that there is not a lot of vegetation beneath the canopy of trees, and the trees themselves are deciduous, meaning they lose their leaves in the winter. The sparse undergrowth allows for more light to reach the forest floor, which can encourage the growth of herbaceous plants and wildflowers. This type of woodland is typically found in regions with a temperate climate, characterized by moderate temperatures and precipitation throughout the year.

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The given description is a characteristic of "mechanically formed sedimentary rocks". These rocks are formed from the accumulation of sediments or fragments of other rocks that have been mechanically weathered and eroded, and then transported by water, wind, or ice to a new location. The sediments are then deposited and compacted, and often cemented together by minerals such as silica, calcium carbonate, or iron oxide, forming a solid rock. Examples of mechanically formed sedimentary rocks include sandstone, shale, and conglomerate, which are made up of grains of sand, clay, and pebbles, respectively. Metamorphic rocks are formed from existing rocks that have been subjected to high temperatures and pressures, causing them to change in composition and texture. Plutonic rocks are igneous rocks that solidified from magma deep within the Earth's crust. Organically formed sedimentary rocks are formed from the accumulation of organic matter such as shells or plant material. Volcanic rocks are igneous rocks that solidified from lava or magma on the Earth's surface.

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(a) Sketch map of Africa

Key: The dark-shaded area is the equatorial forest belt of the Congo Basin, with Kinshasa marked in it. The lightly-shaded area is the Sudan tropical grassland (savanna) belt, with Kano marked in it.

(b) Characteristics of the equatorial forest belt

1. It consists mainly of very tall broad-leaved evergreen trees which form a dense, almost continuous canopy.
2. The trees occur in distinct layers, namely emergents, the main canopy, lower storey and shrub layer.
3. There is dense undergrowth, including ferns, shrubs, climbers (lianas), creepers and epiphytes.
4. The trees are closely spaced and competition for sunlight is intense; consequently, many trees grow straight and have buttress roots for support.
5. The forest is green throughout the year because rainfall is high and well distributed.
6. Tree species are numerous and mixed; valuable hardwoods include mahogany, iroko and obeche.

(c) Importance of the equatorial forest belt to man

1. It supplies valuable timber such as mahogany, iroko and obeche for furniture, building and export.
2. It provides fuelwood, poles, fibres, medicinal plants, fruits and other forest products.
3. Lumbering, sawmilling and wood processing provide employment and income.
4. Plantation agriculture is practised, especially cocoa, rubber, oil palm, coffee and bananas.
5. Hunting and fishing provide food and income for many inhabitants.
6. The forest protects soils from heavy rainfall erosion, helps regulate climate and conserves wildlife.

Detalhes da Resposta

Reasons for the high volume of trade between Nigeria and Japan

1. Complementary economies: the two countries produce different goods and each needs what the other has. Nigeria supplies primary products (crude oil, rubber, cotton, cocoa, timber and other raw materials) while Japan supplies manufactured goods, so exchange is mutually profitable.
2. Japan's demand for raw materials: being a highly industrialised but resource-poor country, Japan needs large quantities of petroleum and industrial raw materials, which Nigeria can provide.
3. Nigeria's demand for manufactured goods: Nigeria imports vehicles, machinery, electronics and other manufactures in which Japan specialises and which are relatively cheap and of high quality.
4. Japan's advanced technology and industrial capacity enable it to produce goods in large quantities for export to markets like Nigeria.
5. Efficient sea transport and shipping: both countries are well served by ocean routes and modern ports, making the bulk movement of goods between them cheap and easy.
6. Large Nigerian market: Nigeria's big population provides a wide market that attracts Japanese manufactured goods, while its foreign-exchange earnings from oil enable it to pay for imports.

Detalhes da Resposta

Lumbering in Zaire (Democratic Republic of Congo)

(a) Areas

• The equatorial rain forest of the Congo (Zaire) Basin, especially along the Congo River and its tributaries and around towns such as Kisangani, Mbandaka and the lower Congo near the coast.

(b) Factors favouring lumbering

• Dense tropical hardwood forest with valuable trees (mahogany, ebony, iroko, obeche) growing over a very large area.
• Hot, wet equatorial climate giving continuous tree growth and quick regeneration.
• The Congo River and its tributaries provide cheap water transport for floating and moving logs to sawmills and ports.
• Labour supply and a demand for timber at home and abroad.

(c) Importance

• Provides timber for building, furniture and fuel.
• Earns foreign exchange from the export of hardwood.
• Gives employment to loggers, sawmill and transport workers.
• Supplies raw material for paper, plywood and other wood industries and yields government revenue.

(d) Problems

• Dense forest and difficult terrain with swamps make felling and haulage hard.
• Mixture of species: valuable trees are scattered among many worthless ones, so much effort yields little.
• Poor transport away from the rivers, and inadequate roads and railways.
• Rapid decay of felled timber by heat, humidity, insects and fungi, and shortage of capital and skilled labour.

(e) Possible solutions

• Build and improve roads and railways and provide modern machinery for felling and haulage.
• Practise selective and scientific forestry with re-afforestation to sustain the forest.
• Treat and preserve timber against decay and pests, and provide capital and training for workers.

Detalhes da Resposta

Fishing in Nigeria

(a) Areas

• Coastal/marine waters along the Atlantic (the continental shelf off Lagos, the Niger Delta and Calabar).
• Inland fresh waters: rivers Niger and Benue, Lake Chad, the Kainji, Jebba and other reservoirs, creeks, lagoons and floodplains.
• Fish farms (ponds) in many parts of the country.

(b) Methods

• Artisanal (traditional) fishing using canoes, hooks and lines, cast nets, traps and baskets in rivers, lagoons and coastal waters.
• Modern/commercial fishing using motorised trawlers and large nets in the deep sea.
• Fish farming (aquaculture) in constructed ponds, and drying/smoking for preservation.

(c) Types of fish

• Marine/salt-water fish: sardines, mackerel, croaker, shrimps/prawns, shark.
• Fresh-water fish: tilapia, catfish (mudfish), Nile perch, mackerel and bonga.

(d) Importance

1. Provides cheap animal protein in the people's diet.
2. Provides employment and income for fishermen, traders and processors.
3. Supplies raw materials to industry (fish meal, canning) and reduces fish imports, saving foreign exchange.
4. Encourages development of related activities (boat building, net making, transport and marketing).

Detalhes da Resposta

(a) Four factors that limit the rate of development in the southern coastlands of Nigeria (the Niger Delta and coastal creek belt)

1. Difficult terrain of swamps and creeks: the waterlogged mangrove and freshwater swamps make road and rail construction very difficult and expensive, hindering movement and settlement.
2. Poor, waterlogged soils and flooding: the low-lying, frequently flooded land is not easily farmed or built upon, limiting agriculture and infrastructure.
3. Prevalence of diseases: the hot, wet, swampy environment breeds mosquitoes and other vectors, causing malaria and water-borne diseases that reduce the labour force.
4. Environmental degradation from oil exploitation: oil spillage and gas flaring pollute farmland, creeks and fishing waters, destroying the livelihood of the people.

Also acceptable: dense forest and difficult access, restlessness/insecurity in oil-producing areas, and inadequate potable water.

(b) Four ways the development of the region can be enhanced

• Provision of infrastructure: construction of raised roads, bridges, jetties, electricity and pipe-borne water to improve access and living conditions.
• Control of pollution and land reclamation: enforcing anti-pollution laws, cleaning up oil spills, stopping gas flaring and reclaiming swampland for use.
• Diversification of the economy: developing fishing, agriculture (rice, oil palm), tourism and small industries so the people are not dependent only on oil.
• Investment in health, education and employment: building hospitals and schools, controlling disease, and creating jobs and community-development projects to raise the standard of living.

Detalhes da Resposta

Irrigation agriculture in the Nile Basin

(a) Need for irrigation

• Egypt and northern Sudan lie in a hot desert climate with very little or no rainfall, so crops cannot grow on natural rain alone.
• The high temperatures cause heavy evaporation, so water must be supplied artificially and continuously.
• Irrigation from the Nile allows farming all year round and makes it possible to feed the dense valley population.

(b) Areas

• The Nile valley and delta in Egypt (from Aswan to Cairo and the delta around Alexandria).
• The Gezira plain in Sudan, between the Blue and White Niles near Khartoum.
• Land along the Blue Nile and around Lake Nasser above the Aswan High Dam.

(c) Methods

• Basin irrigation: the older method of trapping the annual floodwater in basins to soak the land (now largely replaced).
• Perennial (canal) irrigation: water stored by dams such as the Aswan High Dam is led all year through a network of canals to the fields.
• Lift methods: water is raised from the river or canals using the shaduf, the Archimedean screw, the water wheel (sakia) and modern motor pumps.

(d) Crops grown

• Cotton (the leading cash crop of Egypt and the Gezira), sugar cane, rice, wheat, maize, millet, dates and vegetables.

(e) Importance

• Provides food for the dense population and raw material (cotton) for industry.
• Earns foreign exchange from the export of cotton and other produce.
• Provides employment for millions of farmers and supports settlement in an otherwise desert land.
• The dams also supply hydroelectric power and control flooding, aiding overall development.

Detalhes da Resposta

None

Detalhes da Resposta

(a) Advantages and limitations of water transportation

Advantages:

1. It is the cheapest means of moving bulky and heavy goods over long distances.
2. It requires no expensive track construction - the natural waterway or sea is the route.
3. It can carry very large loads (bulk cargo such as oil, grain and ores) in a single voyage.

Limitations:

1. It is very slow compared with road, rail or air.
2. Waterways are interrupted by rapids, waterfalls, shallow water, sand bars and freezing/silting, limiting where ships can go.
3. It can only serve places near the coast or navigable rivers, and cannot reach inland areas directly.

(b) How the limitations can be overcome

• Slowness: use faster, modern powered vessels and combine water transport with road, rail or air for through movement.
• Rapids, waterfalls and shallows: construct canals, locks, dams and by-pass channels, and carry out dredging to deepen and widen channels; build breakwaters and clear sand bars.
• Limited reach inland: develop ports with good road and rail links (container/intermodal transport) so goods can be moved onward to inland destinations; build inland waterways where possible.

Detalhes da Resposta

(a) On an outline map of Africa, show and name

• (i) Latitude 20 degrees N: a line drawn across the Sahara through southern Algeria, northern Niger, Chad and Sudan.
• (ii) The prevailing winds in July: the moist south-west monsoon (South-West Trade / South-West Monsoon) blowing onshore over West Africa from the Atlantic, and the South-East Trades south of the Equator.
• (iii) One cold ocean current in the north: the Canary Current, flowing south along the north-west coast (off Morocco and Mauritania).
• (iv) One warm ocean current in the south: the Mozambique/Agulhas Current, flowing south along the south-east coast (also the warm Guinea Current off West Africa).

(b) Effects of prevailing winds and ocean currents on the climate of one part of Africa

Taking the West African coast (Guinea coast):

• In July the moist South-West Monsoon blows onshore from the warm Atlantic and warm Guinea Current. It is laden with moisture, so as it rises over the land it brings heavy rainfall and gives the coast a long wet season, high humidity and moderate temperatures.
• The warm Guinea Current keeps coastal water and air warm and adds moisture, reinforcing the heavy rains.

By contrast, on the north-west (Saharan) coast the cold Canary Current cools the onshore air; the air holds little moisture and its lower layers are chilled, so instead of rain it produces fog and aridity, helping to keep the coast of Mauritania and the western Sahara dry and desert-like.

Detalhes da Resposta

(a) Sedimentary rock and processes of its formation

A sedimentary rock is a rock formed from the accumulation, compaction and cementation of sediments (fragments of older rocks, mineral particles, or the remains of plants and animals) usually in layers or strata.

Two processes of formation:

• Mechanically formed (clastic): rocks are broken down by weathering and erosion; the fragments (gravel, sand, silt, mud) are transported by water, wind or ice, deposited in layers, then compacted and cemented to form rocks such as sandstone, conglomerate and shale.
• Organically formed: the remains of plants and animals accumulate and are compacted over time; plant remains form coal, while shells and skeletons of marine organisms form limestone. (Chemically formed sedimentary rocks such as rock salt and gypsum arise from evaporation and precipitation of dissolved minerals.)

(b) Importance of sedimentary rocks to man

1. They are the main source of fossil fuels - coal, petroleum and natural gas - which provide energy.
2. They yield valuable minerals and building materials such as limestone (for cement), sandstone, clay, gypsum and rock salt.
3. They weather into deep, fertile soils (e.g. from shales and limestone) that support agriculture, and their porous layers store underground water (aquifers).

Detalhes da Resposta

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(a) Permanent drought and seasonal drought

Permanent drought is the condition of continuous, year-round dryness found in desert and semi-desert areas where rainfall is extremely low and unreliable throughout the year; here farming is impossible without irrigation. Example: the Sahara Desert (or the Namib Desert).

Seasonal drought is the regular dry period that occurs every year during the dry season in regions that otherwise have a wet season; the area is watered for part of the year and dry for the rest. Example: the Sudan/Savanna belt of northern Nigeria (or the tropical grasslands generally).

(b) Causes and effects of drought

Two main causes:

• Failure or lateness of the rains caused by shifts in the rain-bearing winds (e.g. the ITD not moving far enough north).
• Human activities such as deforestation and overgrazing that reduce vegetation cover, lower humidity and encourage desertification.

Two effects:

• Crop failure and death of livestock, leading to famine and hunger.
• Drying up of rivers, wells and water sources, causing water shortage and migration of people (environmental refugees).

(c) Methods of minimizing the effects of drought

1. Provide irrigation and construct dams, wells and boreholes to store and supply water.
2. Afforestation and planting of shelter belts, plus growing drought-resistant crops, to check desertification and conserve moisture.

Detalhes da Resposta

(a) Factors which determine the direction of flow of ocean currents

1. Prevailing (planetary) winds: steady winds such as the trade winds and westerlies drag the surface water along and set currents moving in their direction.
2. Rotation of the Earth (Coriolis force): the Earth's spin deflects currents to the right in the Northern Hemisphere and to the left in the Southern Hemisphere, giving the circular (gyre) pattern.
3. Shape and position of land masses (coastlines): continents obstruct and deflect currents, forcing them to change direction and follow the coasts.
4. Differences in water density (temperature and salinity): cold, salty, denser water sinks and flows towards warmer areas, while warm lighter water flows on the surface, driving the direction of flow.

(b) Effects of ocean currents on the climate of adjacent coasts (with examples)

• Warm currents warm the coast and bring rainfall. The North Atlantic Drift keeps the coasts of north-west Europe (Britain, Norway) mild and ice-free in winter and gives rain. The warm Mozambique Current gives the south-east coast of Africa a warm, moist climate.
• Cold currents cool the coast and cause dryness/desert. The cold Benguela Current beside south-west Africa produces the arid Namib Desert and coastal fog; the cold Canary Current keeps north-west Africa dry; the cold Peru (Humboldt) Current produces the Atacama Desert on the west coast of South America.
• Where warm and cold currents meet (e.g. off Newfoundland where the warm Gulf Stream meets the cold Labrador Current) fogs form and rich fishing grounds develop.

Detalhes da Resposta

(a)(i) Latitude and Longitude

Latitude is the angular distance of a place north or south of the Equator, measured in degrees from the centre of the earth. Lines of latitude (parallels) run from west to east, extend from \(0^\circ\) at the Equator to \(90^\circ\)N and \(90^\circ\)S, and are used to calculate distance between places. Longitude is the angular distance of a place east or west of the Greenwich (Prime) Meridian. Lines of longitude (meridians) run from north to south at right angles to the parallels, extend from \(0^\circ\) to \(180^\circ\)E and \(180^\circ\)W, and are used to calculate local time.

(a)(ii) Standard Time and Greenwich Mean Time

Standard Time is the uniform time adopted by a whole country, usually taken from a chosen central meridian, so that the entire country keeps one clock time and avoids the confusion of many different local times from town to town. For example, Nigeria adopts the meridian \(15^\circ\)E and is one hour ahead of GMT. Greenwich Mean Time (GMT) is the local time along the Prime (Greenwich) Meridian, longitude \(0^\circ\). It is the world reference time from which all countries reckon their own time.

(b) Longitude of place X

Step 1: Find the time difference. From 4:48 a.m. on 4th July to 10:00 a.m. on 5th July is \(29\text{ h }12\text{ min}\). Removing the one full day (24 h) that separates the two dates leaves an actual clock difference of:

\[29\text{ h }12\text{ min} - 24\text{ h} = 5\text{ h }12\text{ min}\]

Step 2: Convert the time difference to longitude (\(15^\circ = 1\) hour, \(1^\circ = 4\) minutes):

\[5\text{ h} = 5 \times 15^\circ = 75^\circ\]

\[12\text{ min} = \frac{12}{4}^\circ = 3^\circ\]

\[\text{Total} = 75^\circ + 3^\circ = 78^\circ\]

Step 3: Since the local time at X is behind GMT, X lies west of the Prime Meridian. Therefore the longitude of place X is \(78^\circ\)W.

Detalhes da Resposta

(a) Map of Nigeria: climatic belts and towns

On an outline map of Nigeria, from south to north, locate and name the four climatic belts and one town in each:

• Equatorial/tropical rain-forest (maritime) belt (far south) - town: Warri (or Port Harcourt).
• Tropical wet-and-dry / Guinea savanna belt - town: Ilorin (or Ibadan).
• Sudan savanna belt - town: Kano.
• Sahel savanna (semi-desert) belt (far north) - town: Maiduguri (or Nguru).

(A neat sketch map with the belts shown as east-west zones and each town marked is required.)

(b) Seasonal pattern of rainfall (Northern Nigeria)

Northern Nigeria has a single, short rainy season and a long dry season. The rains come with the north-ward advance of the moist south-west (tropical maritime) winds, beginning about May-June and ending in September-October, with a peak around August. Total rainfall is low (about 500-1000 mm) and decreases northwards. For the rest of the year the dry north-east trade wind (harmattan) dominates, giving a long dry, dusty season.

(c) Effects of this rainfall pattern on farming

• Farming is concentrated in the short wet season; planting waits for the first rains and harvesting follows before the dry season.
• Only quick-maturing, drought-resistant crops (millet, guinea corn, groundnut, cotton, beans) can be grown.
• The long dry season limits farming to one crop a year unless irrigation (fadama) is used, and encourages livestock rearing.
• Unreliable or late rains bring the risk of drought and crop failure.

Detalhes da Resposta

(a) Combined rainfall and temperature graph

The completed combined graph is shown below. Rainfall is represented by bars against the left-hand vertical scale, while temperature is represented by the line against the right-hand vertical scale.

Month	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Rainfall (mm)	0	0	0	0	60	130	240	300	150	0	0	0
Temperature (°C)	22	25	29	31	32	29	27	26	26	27	25	24

(b) Climatic type

The climatic type is the Tropical Continental (Sudan type) climate.

(c) Reasons

1. The annual temperature range is small: \[32^\circ\mathrm{C}-22^\circ\mathrm{C}=10^\circ\mathrm{C}.\]
2. The mean annual temperature is high: \[\frac{22+25+29+31+32+29+27+26+26+27+25+24}{12}=26.9^\circ\mathrm{C}\approx27^\circ\mathrm{C}.\]
3. Rainfall occurs mainly from May to September, while the remaining months are dry.
4. There is one rainfall maximum, in August, when rainfall reaches 300 mm.

Detalhes da Resposta

(a) Labelled diagram of a simple soil profile

(b) Characteristics of two zones in the soil profile

1. A horizon (topsoil or zone of eluviation)
   • It is dark brown or black in colour and contains much humus. This is because dead leaves, plants and animals decay at or near the surface to form organic matter.
   • It contains many plant roots, earthworms and micro-organisms and has high biological activity. This is because it is close to the surface, where air, moisture and decaying organic materials are readily available.
   • It is often leached of clay and soluble minerals. This is because percolating rainwater washes fine particles and dissolved minerals downward into the B horizon.
2. B horizon (subsoil or zone of illuviation)
   • It is usually lighter in colour than the topsoil and contains little humus. This is because most organic matter is concentrated and decomposes in the A horizon.
   • It is richer in clay, iron compounds and other minerals. This is because materials washed down from the A horizon accumulate in this layer.
   • It is more compact and contains fewer roots and soil organisms. This is because it has less humus, less aeration and fewer nutrients than the topsoil.

Detalhes da Resposta

(a) How each factor has affected world population

(i) Improved medical care: better hospitals, drugs, vaccines, sanitation and maternal/child health services have lowered the death rate, controlled epidemic diseases and raised life expectancy. With births still high in many countries, the fall in deaths has produced rapid population growth (a population explosion).

(ii) Advanced technology and industry: mechanised farming and improved storage have increased food supply, while industrialisation created jobs, wealth and better living standards. This has supported larger populations, though in industrialised nations it has also encouraged smaller families and slower growth, whereas in developing nations improved food and health have boosted numbers. Industry also draws people together, raising population in urban areas.

(b) Factors accounting for high population density in Java

1. Fertile volcanic soils that support intensive cultivation of rice and other crops, feeding a large population.
2. Favourable equatorial/tropical climate with abundant rainfall and high temperatures allowing farming all year (double cropping).
3. Intensive wet-rice (padi) agriculture that yields large amounts of food from small areas of land.
4. Good development of industry, trade, transport and towns (e.g. Jakarta), providing employment that attracts and holds many people.

Detalhes da Resposta

(a)(i) Area of Nigeria mostly affected by desert encroachment

On an outline map of Nigeria the desert-encroachment (desertification) zone lies in the extreme north, along the border with Niger, covering the Sahel/Sudan savanna belt of the far northern states such as Sokoto, Katsina, Kano, Jigawa, Yobe and Borno. This is the semi-arid belt just south of the Sahara.

(ii) Two important towns within the area: Sokoto and Maiduguri (also acceptable: Katsina, Kano, Nguru, Damaturu).

(b) Major causes of desertification

• Low and unreliable rainfall with long dry seasons and recurrent drought in the Sahel, which reduces vegetation cover.
• Deforestation and removal of vegetation for firewood, timber and building, exposing the soil.
• Overgrazing by too many cattle, sheep and goats, which strips the grass cover and tramples the soil.
• Over-cultivation and poor farming methods that exhaust the soil and leave it bare and loose.
• Bush burning and wind erosion that carry away the fine topsoil, leaving infertile sand.

(c) Two possible ways of combating this hazard

1. Afforestation and shelter belts: planting rows of drought-resistant trees (for example neem) to form the Great Green Wall, which binds the soil, checks wind erosion and restores vegetation.
2. Controlled land use: regulating grazing and farming through rotational grazing, reduced herd sizes, controlled cultivation, and providing alternative fuel to reduce firewood cutting, so that the natural cover can recover.

Also acceptable: irrigation and water conservation, and public education on environmental protection.